Report any amount money that is missing from your account even if it is only Cents.
If you see an in your bank account listing an amount which you know you didn’t spend nor authorized, no matter how small it is (cents even), make sure you contact the bank and report the fraud.
Don’t think that the amount is so small that it is not worth the trouble to report it. You have to think big: if the cybercriminals are taking cents from a lot of users, they will end up with a lot of stolen money. You can read here for more details how to react to such an event.
How did you end up in this situation?
There are many elements that can go toward something like this happening to you, many of which are out of your hands. A retailer or website for example, being hacked and having financial details stolen, yours included. There is sometimes nothing you can do to further protect yourself, just be sure that in the case of your information falling into the wrong hands, you contact your bank as soon as you become aware.
Phishing scams are most of the most common methods used by crooks to get your details. Never click on links from financial institutions inc. banks, especially if you hold no accounts with them, so go to the websites directly should you need to. There is a lot of help online about identifying phishing scams, as well as further information on our site about how to recognize phishing scams.
Virus programs, usually trojans are another way for criminals to steal information. It's important to ensure you always have a strong AV running on your devices to ensure there is nothing lurking in the background and you are safe online.
One of the newer ways criminals are stealing information is by using fake applications. Ensure you are only using applications which have been developed and published by the financial institution in question, and stay clear of 3rd party applications for financial services.